You’ll want to head over to the EWWW IO settings, and look for the Background optimization section in the status header. It will potentially tell you why it is blocked, and if it gives the option to re-test, try that first.
If that doesn’t work, send your debug information (Support tab) to https://ewww.io/contact-us/ and reference this thread.
You can also do your own troubleshooting via https://docs.ewww.io/article/42-background-and-parallel-optimization-disabled
I went to the previous version and that message is no longer appearing
The previous version doesn’t use Background mode for scheduled optimization. It uses the older and less reliable method via a long-running wp_cron process instead.
Iam using shared hosting and the hosting company had disabled exec() function for security reasons,,they are only activating it for dedicated server
That has nothing to do with background mode, but if you’re using the free mode of the plugin (rather than the API), then it isn’t doing anything anyway on that webhost. There are a whole bunch of supported webhosts here: https://docs.ewww.io/article/43-supported-web-hosts
